1. Field of the Invention
The present invention relates to an image-forming apparatus connectable to a network, a control method for the image-forming apparatus, and a storage medium which stores a program for causing a computer to execute the control method for the image-forming apparatus.
2. Description of the Related Art
Conventionally, there has been known a print-control apparatus connected to a network. The print-control apparatus is used when a network printer function is provided in an image-forming apparatus. The print-control apparatus is also used for the purpose of extending and supplementing the network printer function provided in an image-forming apparatus in advance. The network printer function is a function of printing out an image corresponding to an image signal inputted from an external apparatus through the network.
As an image-forming apparatus connectable to the network via such a print-control apparatus, for example, besides an image-forming apparatus disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2002-312140, there is an image-forming apparatus shown in FIG. 16.
FIG. 16 is a schematic diagram showing connection of a conventional image-forming system.
As shown in FIG. 16, in the connection of the image-forming system, a terminal apparatus 5009 and a print-control apparatus 5001 are connected on a network 5011. An image-forming apparatus 5007 is connected to the print-control apparatus 5001 via a LAN 5005 and a dedicated line 5006.
The print-control apparatus 5001 includes connectors 5002 and 5003 and an interface 5004 for the dedicated line 5006. The connector 5002 is a connector for a NIC (Network Interface Card) which manages low-layer level connection to the network 5011. The connector 5003 is a connector for a NIC which manages low-layer level connection to the LAN 5005.
A data packet transmitted from the terminal apparatus 5009 to the print-control apparatus 5001 is propagated through the network 5011 and received by the print-control apparatus 5001 via the connector 5002. When the received data packet is determined as print data, the data packet is subjected to data processing by the print-control apparatus 5001. Data packets subjected to the data processing are forwarded from the connectors 5003 and 5004 to be transmitted to the LAN 5005 and the dedicated line 5006. The data packets forwarded to the LAN 5005 and the dedicated line 5006 are received by the image-forming apparatus 5007 via a network interface 5008 and a dedicated transfer interface 5010, respectively.
The image-forming apparatus 5007 receives the data packet and performs print processing on a recording medium such as paper according to a print processing procedure of the image-forming apparatus 5007 per se. When processing other than the print processing is performed, the data packet transmitted to the image-forming apparatus 5007 is also received by the print-control apparatus 5001. After receiving the data packet, the print-control apparatus 5001 applies processing necessary for transmission to the image-forming apparatus 5007 to the received data packet and transmits the data packet to the image-forming apparatus 5007.
The data packet transmitted from the image-forming apparatus 5007 is received by the print-control apparatus 5001. The print-control apparatus 5001 applies processing necessary for transmission to the terminal apparatus 5009 on the network 5011 to the received data packet and transmits the data packet to the terminal apparatus 5009. This is realized by using a network packet transfer technique (NAT/NAPT) for transmitting a data packet transmitted by an image-forming apparatus to a network assuming that the data packet is transmitted by a print-control apparatus.
Such a configuration of the conventional image-forming system provides the advantage that it is possible to use the image-forming apparatus and the print-control apparatus without being conscious of these apparatuses.
However, according to the technological progress in recent years, the related art described above cannot cope with some techniques. Examples of such techniques include techniques which the network transfer technique (NAT/NAPT) cannot cope with. Specifically, the techniques are techniques such as IPv6 (Internet Protocol Version 6) and IPsec (IP Security Protocol).
When IPv6 is adopted, the network transfer technique (NAT/NAPT) used in the related art cannot be used. Therefore, it is necessary to use a new network transfer technique. Further, when IPsec is adopted, a terminal apparatus and an image-forming apparatus exchange keys and, when a network packet is has a rewritten address, communication is immediately finished. Such a technique is an extremely useful technique in view of significance of network security in these days. However, when the image-forming apparatus is connected to the print-control apparatus in the configuration described above, such a technique cannot be used between the image-forming apparatus and the terminal apparatus. This is because a network packet transfer technique implemented in the print-control apparatus is judged as disguising of a network packet by these techniques.
To make it possible to realize the techniques such as IPv6 and IPsec, it is conceivable to change the connection of the print-control apparatus and the image-forming apparatus. However, when the connection is simply changed, the system is user-unfriendly.
As an example, in a system in which a print-control apparatus and an image-forming apparatus are connected to an identical network, when a user performs print operation in the image-forming apparatus attached with the print-control apparatus from a terminal apparatus, problems described below occur. The user does not understand which of network addresses of the print-control apparatus and the image-forming apparatus should be designated. Therefore, the system confuses the user and is user-unfriendly. When, for example, the user performs device search using an application program and searches for a device on a network, since both the print-control apparatus and the image-forming apparatus are detected, the user is confused.